Rev. 1.0, 02/00, page 454 of 1141
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Operation in Case of Mode Transition
Transmission
Operation should be stopped (by clearing TE, TIE, and TEIE to 0) before making a module
stop mode, standby mode, watch mode, subactive mode, or subsleep mode transition.
TSR1, TDR1, and SSR1 are reset. The output pin states in module stop mode, standby
mode, watch mode, subactive mode, or subsleep mode depend on the port settings, and
becomes high-level output after the relevant mode is cleared. If a transition is made during
transmission, the data being transmitted will be undefined. When transmitting without
changing the transmit mode after the relevant mode is cleared, transmission can be started
by setting TE to 1 again, and performing the following sequence: SSR1 read
TDR1
write
TDRE clearance. To transmit with a different transmit mode after clearing the
relevant mode, the procedure must be started again from initialization. Figure 22.24 shows
a sample flowchart for mode transition during transmission. Port pin states are shown in
figures 22.25 and 22.26.
Reception
Receive operation should be stopped (by clearing RE to 0) before making a module stop
mode, standby mode, watch mode, subactive mode, or subsleep mode transition. RSR1,
RDR1, and SSR1 are reset. If a transition is made without stopping operation, the data
being received will be invalid. To continue receiving without changing the reception mode
after the relevant mode is cleared, set RE to 1 before starting reception. To receive with a
different receive mode, the procedure must be started again from initialization.
Figure 22.27 shows a sample flowchart for mode transition during reception.